It's kind of your choice which way to go on this. You have the right pump and the sender location is good.
You have not dealt with the issue of thermal shock.
I think you have a modified system now and it was done for rapid warm up. After all, the Montreal winters aren't exactly tropical are they?
If you choose to stay with the current set up and just change to a new thermostat there is one thing I would highly recommend (if you haven't already) and that is run a full synthetic engine oil and an expanded capacity oil pan.
You may have been getting by already on the strength and resilience of your oil. But oiling is supposed to help in that respect.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.